Navigation And Local Thermometry

ABSTRACT

A system including a thermal sensor with an instrument placed in a volume. The thermal sensor may be useful in determining a temperature at a surface of the instrument and a distance away from the instrument. A therapy may be performed based on a sensed temperature with the thermal sensors.

FIELD

The subject application relates generally to a temperature measuring system, and particularly to a system for measuring a temperature within a volume.

BACKGROUND

A procedure can be performed on a subject that may include heating a selected portion of a subject. For example, a heating device can be positioned within a portion of the subject to heat the portion of the subject. After heating a portion of the subject, changes may occur at or near the device generating the heat or thermal energy. During a surgical procedure, selected tissues may die due to the generated heat. After a selected period of time the device generating the thermal energy may be removed to complete at least a portion of the procedure.

SUMMARY

When performing a procedure on a subject, tissues may be interacted with to create a selected result. For example, tissues may be heated to a selected degree to kill the tissue. For example, tumors may be heated to be killed. The tissues may then be removed with various processes, such as natural waste removal processes. The tumor may also be heated to a degree to completely remove the tissue.

It is understood, however, that non-human tissue or non-living structures may also be acted upon. For example, an instrument can be positioned within a non-living structure to heat or interact with a select portion of the structure to obtain a select result. For example, an instrument or a probe may be positioned within a volume of water or a gelatin material to interact with a selected portion of the structure.

To interact with a structure or volume, it may be selected to heat a portion of the volume to a selected temperature. Measuring the temperature within the volume, however, may include measuring a temperature of the structure a selected distance away from the surface of the instrument. For example, an instrument can be inserted into the volume. The instrument can heat tissue or a portion of the volume substantially adjacent to the instrument and the thermal energy may transfer away from the instrument. Such transfer of thermal energy may be dependent on the type of tissue, circulation around the instrument, and other factors. Accordingly, a precise determination of the temperature at a distance away from the instrument may be difficult to determine and/or predict. Accordingly, a temperature sensing instrument can be incorporated into the instrument to measure a temperature a distance away from the instrument heating the volume.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 is an environmental view of an operating theatre including an optional imaging system and a navigation system;

FIG. 2 is a schematic view of a laser heating system;

FIG. 3 is a schematic illustration of a use of the laser heating system, according to various embodiments;

FIG. 3A is a detail view of a display device illustrating icons of an instrument and a temperature profile;

FIG. 4 is a detail view of a distal end of an instrument of the laser heating system;

FIG. 5 is a detail cross-sectional view of a distal end of a housing of the instrument of the laser heating system;

FIG. 6 is a detail cross-sectional view of a distal end of an energy delivery component of the instrument of the laser heating system; and

FIG. 7 is a flowchart illustrating operation of an energy delivery system.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

Illustrated in FIG. 1 is a diagrammatic overview of a system including various components, such as a navigation system 10 and an imaging system 12. The various components may be included in a surgical suite or may be in separate locations for various portions of a procedure on a patient 14 or any appropriate selected subject. Non-human and non-living subjects may also be subjected to a procedure using the various components illustrated in FIG. 1.

The navigation system 10 can be used to navigate a device (e.g. a medical device 200 as discussed further herein) into or relative to the subject 14. A tracking system 29 may be used to track the device 200 to assist in determining a position (including location and orientation). The device may include an implant or an instrument that is moved relative to the subject 14. It should further be noted that the navigation system 10 may be used to navigate any type of instrument, implant, or delivery system, including: guide wires, arthroscopic systems, orthopedic implants, spinal implants, deep brain stimulation (DBS) leads, cardiac pacing leads, ablation instruments, etc. Moreover, the instruments may be used to navigate or map any region of the body. The navigation system 10 and the various tracked items may be used in any appropriate procedure, such as one that is generally minimally invasive or an open procedure.

The navigation system 10 can interface with the imaging system 12 that is used to acquire image data of the subject or patient 14. The image data may be pre-operative, intra-operative, or post-operative, or real-time image data of the patient 14. The real time image data may be substantially instantaneous image data that may allow a user 54 and/or various processing units, as discussed herein, to analyze a portion of the subject 14 to act upon during a procedure. It will be understood by one skilled in the art, any appropriate subject can be imaged and any appropriate procedure may be performed relative to the subject. The subject may be a human patient and the procedure may be a surgical procedure, such as an implantation of a device (e.g. a screw, lead, etc.).

Exemplarily illustrated in FIG. 1, the imaging system 12 includes a magnetic resonance imaging (MRI) system. The MRI system may be operated in a manner that is generally understood by one skilled in the art. Exemplary MRI systems include the SIGNA™ MRI sold by the General Electric Company; the SIGNA™ MRI is available in various configurations. The imaging system may, however, also include an O-arm® imaging device sold by Medtronic Navigation, Inc. having a place of business in Louisville, Colo., USA, the imaging system may include those discloses in U.S. Pat. Nos. 7,188,998; 7,108,421; 7,106,825; 7,001,045; and 6,940,941; all of which are incorporated herein by reference or other appropriate imaging system, including x-ray C-arm systems, PET imaging systems, etc.

The imaging device 12 may have a gantry housing 20 that encloses an image capturing portion 22. The image capturing portion 22 may include portions generally used in a MRI, including magnets, radio frequency (RF) emitters and receivers, etc. An x-ray imaging system may include an x-ray source or emission portion and an x-ray receiving or image receiving portion located generally or as practically possible 180 degrees from each.

The position of the image capturing portion 22 can be precisely known relative to any other portion of the imaging device 12. In addition, as discussed herein, the precise knowledge of the position of the image capturing portion 22 can be known or determined with the imaging processing system or with the tracking system 29. The position of the image capturing portion 22, while gathering image data, may be used during navigation of the device 200. The position of the patient 14 may also be determined by tracking a patient tracking device 48 that may be placed on the patient 14 to track the patient 14 during image data acquisition.

The tracking system 29 can include various portions that are associated or included with the navigation system 10. The tracking system 29 can also include a plurality of types of tracking systems including an optical tracking system that includes an optical localizer 40 and/or an electromagnetic (EM) tracking system that can include an EM localizer 42. The optical localizer 40 may “view” or optically track trackable portions (tracking devices) with cameras. The EM localizer 42 may generate a field and a trackable portion (e.g. EM tracking device) may sense the field to determine a location relative to another tracking device in the field. One skilled in the art will also understand that the EM tracking device may emit a signal that is sensed or received by the localizer 42 for determining a position of the tracking device. Various tracking devices, including those discussed further herein, can be tracked with the tracking system 29 and the information can be used by the navigation system 10 to allow for a display of a position of an item. Briefly, tracking devices, such as the patient tracking device 48, an imaging device tracking device 50, and an instrument tracking device 52, 370, allow selected portions of an operating theater to be tracked relative to one another with the appropriate tracking system 29, including the optical localizer 40 and/or the EM localizer 42.

It will be understood that any of the tracking devices 48-52 can be optical or EM tracking devices, or both, depending upon the tracking localizer used to track the respective tracking devices. It will be further understood that any appropriate tracking system can be used with the navigation system 10. Alterative tracking systems can include radar tracking systems, acoustic tracking systems, ultrasound tracking systems, and the like.

An exemplarily EM tracking system can include the STEALTHSTATION® AXIEM™ Navigation System, sold by Medtronic Navigation, Inc. having a place of business in Louisville, Colo. Exemplary tracking systems are also disclosed in U.S. Pat. No. 8,644,907, issued Feb. 4, 23012, titled “Method And Apparatus For Surgical Navigation”; U.S. Pat. No. 7,751,865, titled “Method And Apparatus For Surgical Navigation”, issued Jul. 6, 2010; U.S. Pat. No. 5,913,820, titled “Position Location System,” issued Jun. 22, 1999 and U.S. Pat. No. 5,592,939, titled “Method and System for Navigating a Catheter Probe,” issued Jan. 14, 1997, all incorporated by reference herein.

Further, for EM tracking systems it may be necessary to provide shielding or distortion compensation systems to shield or compensate for distortions in the EM field generated by the EM localizer 42. Exemplary shielding systems include those in U.S. Pat. No. 7,797,032, titled “Method and system for navigating a catheter probe in the presence of field-influencing objects”, issued on Sep. 14, 2010 and U.S. Pat. No. 6,747,539, titled “Patient-shielding and coil system”, issued on Jun. 8, 2004, all of which are incorporated herein by reference. Distortion compensation systems can include those disclosed in U.S. Pat. No. 6,636,757, titled “Method and apparatus for electromagnetic navigation of a surgical probe near a metal object”, issued on Oct. 21, 2003, all of which are incorporated herein by reference.

With an EM tracking system, the EM localizer 42 and the various tracking devices can communicate through an EM controller 44. The EM controller may include various amplifiers, filters, electrical isolation, and other systems. The EM controller 44 can also control one or more conductive coils of the localizer 42 to either emit or receive an EM field for tracking. A wireless communications channel, however, such as that disclosed in U.S. Pat. No. 6,474,341, entitled “Surgical Communication Power System,” issued Nov. 5, 2002, herein incorporated by reference, can be used as opposed to being coupled directly to the EM controller 44.

It will be understood that the tracking system may also be or include any appropriate tracking system, including a STEALTHSTATION® TRIA®, TREON®, and/or S7™ Navigation System having an optical localizer, similar to the optical localizer 40, sold by Medtronic Navigation, Inc. having a place of business in Louisville, Colo. Optical tracking systems may also include those disclosed in U.S. Pat. No. 8,010,177, Aug. 30, 2011, Intraoperative Image Registration” and/or U.S. Pat. No. 6,235,038, issued on May 22, 2001, titled “System For Translation Of Electromagnetic And Optical Localization Systems”, all incorporated herein by reference.

Although discussed herein is the EM tracking system using the EM localizer 42, it is understood that other appropriate tracking systems may be used in place of the EM tracking system or to augment the EM tracking system. Further alternative tracking systems are disclosed in U.S. Pat. No. 5,983,126, to Wittkampf et al. titled “Catheter Location System and Method,” issued Nov. 9, 1999, which is hereby incorporated by reference. Other tracking systems include an acoustic, radiation, radar, etc. tracking or navigation systems.

The imaging system 12 can further include a separate image processing unit 58 that can be housed in a selected location, such as on a server system, in a remote access location, or at a local location such as in a cart 56. The navigation system 10 can include the navigation processing unit 60 that can communicate or include a memory 62. The memory 62 may also communicate with the image processing unit 58. The memory 62 may be a selected non-transient computer readable memory. Exemplary memory systems may include dynamic random access memory (DRAM), magnetic alterable media, physical read/write media, and the like. The memory 62 may store various information or instructions, including computer executable instructions. The navigation processing unit 60 can receive information, including image data, from the imaging system 12 and tracking information from the tracking systems 29, including the respective tracking devices 48-52 and the localizers 40-42. Image data can be displayed as an image 64 on a display device 66 of a workstation or other computer system 68. The workstation 68 can include appropriate input devices, such as a keyboard 70. It will be understood that other appropriate input devices can be included, such as a mouse, a foot pedal or the like. The various processing units and computers or workstations may include internal or local memory and processing units. The processing units may include central processing units that are general computers that execute instructions to perform tasks on a chip. The processing units may also be or include circuits, such as specific circuits including application specific integrated circuits (ASIC). Accordingly, the processing units may be devices that receive information and execute instructions that are stored or received based on the information.

The image processing unit 58 receives and/or processes image data from the imaging system 12 and transmits it to the navigation processing unit 60. It will be further understood, however, that the imaging system 12 need not perform any image processing and it can transmit the image data directly to the navigation processing unit 60. Accordingly, the navigation system 10 may include or operate with a single or multiple processing centers or units that can access single or multiple memory systems based upon system design. The imaging processing unit 58 may also be used to control the imaging system 12. Further, the imaging processing unit may be used to determine selected positions or areas of interest of the patient to image based on selected inputs and/or instructions. For example, a tracked position of the instrument 200 may be determined and transmitted to the image processing unit 58 and the region of the patient 14 around the tracked position of the instrument 200 may be selected to be imaged.

The patient 14 can be fixed onto a table 72, but is not required to be fixed to the table 72. The table 72 can include a plurality of straps 74. The straps 74 can be secured around the patient 14 to fix the patient 14 relative to the table 72. Various apparatuses may be used to position the patient 14 in a static position on the operating table 72. Examples of such patient positioning devices are set forth in commonly assigned U.S. patent application Ser. No. 10/405,068, published as U.S. Pat. App. Pub. No. 2004/0199072, entitled “An Integrated Electromagnetic Navigation And Patient Positioning Device”, filed Apr. 1, 2003, which is hereby incorporated by reference. Other known apparatuses may include a Mayfield® clamp.

Also, the position (including three-dimensional location and orientation) of the patient 14 relative to the imaging system 12 can be determined by the navigation system 10 with the patient tracking device 48 and the imaging system tracking device 50. The imaging system 12, such as the MRI can know a position at which image data is acquired and can be repositioned or operated to acquire image data at the same position at a later time. Knowing the relative position of the patient 14 may then allow the patient 14 to also be repositioned to collect a second image data later than a first image data of substantially the same region of the patient 14.

Subject or patient space (a volume in and around the patient in real space) and image space (a volume defined by the image data) can be registered by identifying matching points or fiducial points in the patient space and related or identical points in the image space. The imaging device 12 can be used to generate image data at a precise and known position. This can allow image data that is automatically or “inherently registered” to the patient 14 upon acquisition of the image data. Essentially, the position of the patient 14 is known precisely relative to the imaging system 12 due to the accurate positioning of the imaging system 12 relative to the patient 14. Also, the exact position of the area from which image data is acquired is known or can be determined. This allows points in the image data to be known relative to points of the patient 14 because of the known precise location of the imaging system 12.

Alternatively, manual or automatic registration can occur by matching fiducial points in image data with fiducial points on the patient 14. Registration of image space to patient space allows for the generation of a translation map between the patient space and the image space. According to various embodiments, registration can occur by determining points that are substantially identical in the image space and the patient space. The identical points can include anatomical fiducial points or implanted fiducial points. Exemplary registration techniques are disclosed in Ser. No. 12/400,273, filed on Mar. 9, 2009, now published U.S. Pat. App. Pub. No. 2010/0228117, incorporated herein by reference.

Once registered, the navigation system 10 with or including the imaging system 12, can be used to perform selected procedures. Selected procedures can use the image data generated or acquired with the imaging system 12. Further, the imaging system 12 can be used to acquire image data at different times relative to a procedure. As discussed herein, image data can be acquired of the patient 14 subsequent to a selected portion of a procedure for various purposes, including confirmation of the portion of the procedure.

With continuing reference to FIG. 1, the imaging system 12 can generate actual or virtual three dimensional images of the patient 14. The patient 14 can be placed relative to the imaging system 12 to allow the imaging system 12 to obtain image data of the patient 14. To generate 3D image data, the image data can be acquired from a plurality of views or positions relative to the patient 14. The 3D image data of the patient 14 can be used alone or with other information to assist in performing a procedure on the patient 14 or an appropriate subject. It will be understood, however, that any appropriate imaging system can be used, including magnetic resonance imaging, computed tomography, fluoroscopy, etc. to acquire image data (including 3D image data) of the patient 14.

As noted above, with reference to FIG. 1, the surgical navigation system 10 can be used to navigate the instrument 200 for a selected procedure. With additional reference to FIG. 2, according to various embodiments, the device may be a laser energy system 202 that may be used to perform a selected procedure on a subject, such as the human patient. The laser system 202 can include the laser system as disclosed in U.S. Pat. No. 7,270,656; U.S. Pat. No. 8,211,095; U.S. Pat. No. 8,851,080; and U.S. Patent Application Publication No. 2012/0245573 published on Sep. 27, 2012, all of the above incorporated herein by reference.

Generally, the laser system 202 includes the instrument 200. The instrument 200 may include a housing 210 which may be rigid, flexible, or semi-rigid. For example, the housing 210 can be formed to include a selected rigidity for insertion into a patient, such as into brain tissue of the subject through a selected bore formed in a skull of the subject. The housing may include or define an internal bore. The internal bore may be blind bore that is terminated at a distal end by a distal tip 212. The distal tip 212 may be substantially solid and may include an exterior cutting surface, if selected. The laser system 202 generally includes an energy delivering component 214 that may be housed in in the housing and extends from a proximal portion 216 that can be coupled to an energy source 218. The energy source may be in a housing 204 and connected with a line 219 (e.g. a fiber optic line which may have a cladding 219 a) with the energy delivery component 214.

The energy delivery component 214 can extend from the proximal end 216 to a distal end 220. At the distal end 220 the energy delivery component 214 can deliver energy from the energy source 218 to create a selected result. For example, the energy source 218 can deliver a selected light energy (such as a laser light energy) to the proximal end 216 of the energy delivery component 214. The energy delivery component 214 may act as a wave guide so that the light energy travels to the distal end 220 to be emitted. For example, the housing 210 may be transparent such that the light energy is emitted through the housing 210 to effect adjacent tissue and the tissue that is a distance from the housing 210. For example, as discussed herein, the housing 210 can include an exterior surface 230. Therefore, some matter, such as brain tissue, may contact the exterior surface 230 and receive the light energy. Further, tissue that is a distance away from the surface 230, such as a distance 232 may also receive a selected amount of the energy from the energy delivery component 214.

As the energy is received and absorbed in the tissue, including the tissue that may contact the surface 230 of the housing 210 and tissue that is the distance 232 away from the housing 210, a temperature increase may occur in the tissue. As illustrated in FIG. 3, the device 200 may be positioned within a portion of the patient 14. The distal solid end of the housing 212 may penetrate to a selected region and the energy delivery component 214 can be positioned within the housing 210. As also illustrated in FIG. 3, tissue may contact the external surface 230 of the housing 210 and the tissue may also be positioned the distance 232 away from the housing 210. The thermal energy may be directed at a selected region or region or area of interest 250. The region of interest may include a tumor (schematically illustrated in FIG. 3). The tissue may be heated to a selected degree when energy is delivered through component 214, including tissue that contacts the housing 210 at the surface 230 and the tissue at the distance 232 away from the housing 210.

According to a selected procedure, heating the tissue to a selected degree may include heating the tissue to a specific temperature or within a specific temperature range. To assist in achieving a selected temperature, a cooling system 260 may also be included within the housing 204. The cooling system 260 may assist in regulating a temperature of the device 200.

The cooling system 260 may include a cooling medium supply 262 that delivers a cooling medium to an inlet port 264 through a supply line 265 into the housing 210. An exit port 266 can allow used or waste coolant to exit the housing 210 through line 267. In various embodiments, the cooling material can be recycled into the cooling medium supply 262 or may be delivered to a waste container 268.

The cooling medium from the cooling supply 262 may travel through passages formed within the housing 210 at least by a first assembly or sheath 280. The sheath 280 may extend along at least a selected portion of the length of the energy delivery component 214 and form a first channel 282 that allows for direct contact between the energy delivery component 214 and the cooling fluid and a second channel 284 that is formed between an inner wall of the housing 210 and the sheath 280. Again, flow of a coolant for cooling the medical instrument 200 is disclosed in U.S. Patent Application Publication 2012/0245573, incorporated herein by reference.

During use the energy delivered by the energy delivery component 214 heats the tissue, such as the tissue of the region of interest 250. The temperature selected to be achieved in the region of interest 250 can be based on various factors, including the size of the tumor, type of tumor, or other selected features. Further, different procedures may require or select a different temperature or temperature range, such as affecting healthy brain tissue for a selected region or for affecting the delivery of a pharmaceutical, such as a heat activated pharmaceutical. Nevertheless, a temperature of the tissue within the region of interest 250 may be selected to be determined.

A temperature sensing component may be used to assist in measuring a temperature of the region of interest 250. One or more temperature components may be included in the laser system 202. In various embodiments, as illustrated in FIG. 4, a first temperature sensing component 290 a and a second temperature sensing component 290 b can be incorporated into the instrument 200. The temperature sensing components 290 a, 290 b can be substantially similar or identical to one another, but be positioned at different locations, such as at opposite sides of the instrument 200 or at any appropriate angularly offset position relative to one another. Further, it will be understood, that the temperature sensing components 290 a, 290 b can be positioned axially along a length of the instrument 200. For example, the temperature sensing components can be substantially equally spaced along a length of the energy delivery component 214, such as a third temperature sensing component 290 c may be axially spaced from the first and second temperature sensing component 290 a, 290 b. Also, the third temperature sensing component may include a plurality of the third temperature sensing component any may also be at various circumferential positions around the energy delivery component 214.

As discussed above, the temperature sensing component 290 a, 290 b, and 290 c may all be substantially identical temperature-sensing components such as those discussed herein. For example, the temperature sensing components 290 a, 290 b, and 290 c may all be distant temperature-sensing components that sense a temperature distant or a relative temperature at a distance from the exterior surface 230 at the housing 210. It is further understood that additional temperature-sensing components, including a fourth temperature-sensing component 290 d and a fifth temperature-sensing component 290 e may be included with the laser system 202 such as being incorporated into the instrument 200. The fourth and fifth temperature-sensing components 290 d, 290 e may be axially and angularly positioned relative to the other temperature-sensing components 290 a, 290 b, and 290 c and any appropriate number may be included in the instrument 200. According to various embodiments, fourth and fifth temperature-sensing component 290 d, 290 e may be a different type of temperature-sensing component than the first through third temperature-sensing components 290 a, 290 b, and 290 c. For example, the fourth and fifth temperature-sensing components 290 d, 290 e may be contact temperature-sensing components, including those discussed further herein. The contact temperature-sensing components can be used to measure or determine a temperature substantially adjacent to the surface 230 of the housing 210. Therefore, temperature-sensing components can include those that measure a temperature both at the surface 230 and a distance away from the surface 230 of the instrument 200. This may allow the laser system 202 to be used to determine temperatures at different locations relative to the housing 210, as discussed above and allowed to be illustrated as the icon 292′.

Further, the temperature-sensing component 290 a-290 e can be incorporated into the housing or relative to the energy conducting component 214 in various manners. For example, the temperature-sensing components 290 a-290 e may be embedded into the housing 210 near the surface 230. Various processes may be used such as co-extrusion or molding of the temperature-sensing components 290 a-290 e into the housing 210. According to various embodiments, the temperature-sensing components may also be encased between a surface of the housing 210 and an optional exterior coating or layer 293 that may be positioned over the temperature-sensing components 290 a-290 e. The exterior surface of the overcoating 293 (illustrated in phantom) would then be the exterior surface 230 of the housing 210. The exterior surface of the overcoating 293 would be the surface that is in direct contact with a volume, including the tissue of the subject 14. It is understood, however, that various manufacturing techniques may be employed to position the temperature-sensing components 290 a-290 e with the instrument 200.

The temperature sensing component(s), regardless of the number included with the medical device 200, can include an ability to measure or sense a temperature in the region of interest. The temperature sensors components may sense a temperature at the surface 230 and at various selected distances from the surface 230 of the housing 210, including at least the distance 232 away from the surface 230 of the housing 210.

Various temperature sensors can include direct temperature sensors such as thermistors, thermo-couples, or resistance temperature detectors, which can include thin film resistant temperature detectors. One example of a contact or direct temperature sensor includes the sensor disclosed in D H Kim et. al., Materials for multifunctional balloon catheters with capabilities in cardiac electrophysiological mapping and ablation therapy, Nature Materials, 10, 316-323 (March 2011), doi:10.1038/nmat2971. The direct temperature sensors are able to sense a temperature or measure a temperature substantially in contact with the temperature sensor. Therefore, the temperature sensor 290 a, 290 b can measure a temperature substantially at the surface 230 of the housing 210.

The temperature sensor 290 a, 290 b however, may also include more than one type of temperature sensor. Accordingly, indirect temperature sensors may also be included with one or more temperature sensors 290 a, 290 b. For example, two temperature sensors may be positioned relative to another, such as next to one another, to form the temperature sensor components 290 a, 290 b. Each of the temperature sensor components 290 a, 290 b may measure both a direct temperature at the surface 230 and a temperature at least at the distance 232 away from the surface 230.

Indirect temperature sensors may be used to measure a temperature at least the distance 232 away from the surface 230 in various manners. For example, indirect temperature sensors can include a low frequency response, including mechanical response or elastic response in an electromechanical transducer. High frequency response, such as a high frequency mechanical ultrasound response can also be used, such as in piezoelectric sensor or ultrasound temperature sensors as discussed below. Electrical capacitors and resistance may also be used to sense a temperature at a distance from the surface 230.

Further indirect temperature sensors can include sensing channels that can sense or receive optical emissions. For example, the temperature sensor components 290 a, 290 b can include a sensor or optical channel that receives an optical emission from black body radiation or chemical fluorescent such as photoelectric sensors (e.g., polyallylamine hydrochloride thin film or optical fiber receptors). The perceived or sensed optical or infrared emissions can be analyzed for intensity or frequency or both (e.g. spectroscopically). Further optical coherence tomography or optical scattering can also be analyzed at optical sensors based upon a transmission from a fiber optic element and sensing return of interference intensity, and frequency analysis.

In various embodiments, the ultrasound temperature sensors can include sensors such as those disclosed in Q Zhou et. al. Piezoelectric films for high frequency ultrasonic transducers in biomedical applications, Prog. Mater. Sci. 56, 139-174, (2011), doi:10.1016/j.pmatsci.2010.09.001). The temperature sensors can generally sense a range of temperatures of about 30° Celsius (C) to about 90° C. Alternatively, the temperature sensors can be used to determine a differential or boundary of a differential such as about a 1° difference to about a 5° difference. Further various optical or sensing channel temperature sensors can include the temperature sensor Fiber Optic Temperature Probe PRB-MR1 sold by OSENSA Innovations Corp. having a place of business at Coquitlam, BC, Canada.

The temperature sensor components 290 a, 290 b can transmit the sensed information, such as ultrasound reflections or optical information and transmit the information along transmission lines 300 a and 300 b, respectively. The transmission lines 300 a and 300 b can include wired or wireless transmissions to a selected analyzing system, including the navigation processing unit 60 or the imaging processing unit 58. It is understood that the laser system 202 may also include a laser system processing unit 310. The laser system processing unit 310 may be similar to the other processing units, and all of the processing units may be incorporated as computer executable instructions on one processing unit. Nevertheless, the laser processing unit may receive signals from the temperature sensor components 290 a, 290 b via the lines 300 a, 300 b. The laser processing unit 310 may also alter operation or provision of power to the energy conducting component 214 based on the sensed temperature and determined operation of the laser system 202 for a selected procedure.

Alternatively, or in addition to a wire provided within the housing 210, the transmission lines 300A, 300B may be traces formed into an interior wall of the housing 210 or onto the sheath 280. Nevertheless, the sensed information can be transmitted along the transmission lines 300A, 300B to a selected processing unit to determine a temperature sensed with a selected temperature sensor.

The temperature sensors 290 a, 290 b may, therefore, be used to determine a temperature profile that may be illustrated as an icon 292′ (FIG. 3A) within the region of interest 250 relative to the device 200. At least because the temperature sensors 290 a, 290 b are able to sense a temperature at least a selected distance, such as the distance 232, spaced away from the surface 230, the temperature profile 292 may include a three-dimensional or two-dimensional profile or gradient of temperature(s) that is determined within a volume, such as the region of interest 250. The determined temperature profile 292 can be determined based upon a sensed temperature at a plurality of positions relative to the device 200. The plurality of sensed temperatures at the plurality of positions can then be combined to determine a 2D or 3D volume profile of temperature within the region of interest 250.

The temperature profile 292 may be used to determine if a therapy, such as a thermal therapy, is progressing as planned or has reached or achieved a planned temperature. As discussed herein, the temperature sensed by the temperature sensors 290 a, 290 b either alone or in combination with the determined temperature profile may be used as a part of a therapy method or method of operating the laser system 202. Further, the temperature profile may be illustrated as an icon 292′ superimposed on an image of the region of interest, such as with the display 66, to illustrate the temperature profile relative to the region of interest. This is due, at least in part, to navigation of the instrument via the navigation system 10, as discussed further herein.

For example, with reference to FIGS. 1, 3 and 3A the image of the patient 64 may include an instrument icon 460 that illustrates and represents the determined position of the instrument 200. Based on one or more sensed temperatures, the temperature profile 292 may be illustrated as an icon 292′ relative to the instrument and superimposed on the image 64. Further, it is understood that a temperature gradient may exist as the temperatures may vary between different positions. Thus, the temperature profile icon 292′ may include gradient lines or areas. The icon may, therefore, represent a physical temperature image of the measured temperature profile. For example, as illustrated in FIG. 3A, the temperature profile icon 292′ may include a first gradient area 292′a, a second gradient area 292′b, and a third gradient area 292′c. In each of the gradient areas 292′a, 292′b, and 292′c the determined temperature may be different. It is understood that more or less than three gradient areas may be shown and that the gradients need not be generally concentric but may be determined and illustrated in pockets or discrete portions relative to one another.

The temperature profile 292 may be determined and illustrated as the icon 292′ at least because the temperature sensors 290 a, 290 b may be operated to determine a temperature at different positions at the surface 230 and distances away from the surface 232. The temperature profile may include a determination of a plurality of temperatures at or over a selected period of time, such as over ten seconds. The determined temperatures at different positions may then be illustrated as the icon 292′.

According to various embodiments, the medical device 200 can be delivered to a patient, such as to the region of interest 250, as illustrated in FIG. 3, by positioning the housing 210 at selected position and then moving the energy delivery component 214 into the housing 210. The navigation system 10 can be used to navigate the medical device 200, including either or both of the housing 210 or the energy providing component 214 to a selected position.

In various embodiments the medical device tracker 52 can be formed as one or more coils of conductive material within the housing 210. With reference to FIG. 5, the tracking device 52 within the housing 210 can include one or more coils of wire or traces of conductive material 342 that are formed substantially around or on an interior surface 350 of the housing 210. It is understood that the coils of conductive material 342 may also or alternatively be formed into the housing 210, as illustrated by phantom coils 342 a. The coils or wire 342 may sense or transmit an electromagnetic field that is sensed or transmitted by the localizer 42.

The tracking device, it is understood, may include a plurality of the coils 342. Further, discrete coils may be formed at angles relative to one another. Multiple angles may assist in providing multiple degrees of freedom of position (including 3 degrees x,y,z of location and 3 degrees of yaw, pitch and roll of orientation). The housing 210 can be positioned into the patient 14 using various systems such as a trajectory guide 360, as illustrated in FIG. 1. The tracking device 52 may be formed as disclosed in U.S. Pat. No. 8,644,907 issued on Feb. 4, 2014, incorporated herein by reference.

The trajectory guide 360 can include any appropriate trajectory guide such as the NAVIGUS® trajectory guide sold by Medtronic, Inc. having a place of business in Minnesota, USA. Other trajectory guides can include trajectory guides as disclosed in U.S. Patent Application Publication No. 2013/0053867 published on Feb. 20, 2013, incorporated herein by reference. The trajectory guides can assist in guiding or holding a portion of the device 200 as it is moved into the patient 14 by the user 54. The guide 360 can also be fixed at a selected position relative to the patient to allow movement of a device 200 along a selected trajectory or path into the patient 14.

Further, various individual or discrete coils, such as microcoils, can be positioned at various locations within the housing or on the housing 210. For example, detector devices 52 can include one or a plurality of microcoils 343 a, 343 b, 343 c. The microcoils 343 a-c can be positioned at various locations relative to one another such as including a common center and extending along orthogonal axes relative to one another, or may include a non-common center, but still positioned at three orthogonal axes relative to one another. It is further understood that less than three of the microcoils 343 a-c may be provided and still allow for appropriate tracking of the instrument 200. Again, the microcoils 343 a-c may be included within the housing 210 according to various embodiments such as an insertion into the housing or co-extrusion or molding into the housing 210. Regardless, the microcoils 343 a-c may be used alone or in combination with the conductive coils 342, 342 a.

Further, with reference to FIG. 6, the energy delivery component 214 may also include a second or separate tracking device 370. The tracking device 370 may also include one or more conductive coil elements 376 that may be formed at various angles relative to one another, such as those disclosed in U.S. Pat. No. 8,644,907 issued on Feb. 4, 2014, incorporated herein by reference. The coil elements 376 may include conductive wire wrapped around or inside of the energy transmission component 214. Alternatively, or in addition thereto, the coil elements 376 may be conductive traces formed around an outside of the energy transmission component 214.

Again the tracking device 370 can either generate or receive electromagnetic fields that are either received from or transmitted to the localizer 42. The navigation processing unit 60 can determine a position of the tracking device 370 based on the sensed fields. Further, the tracking device 370 can be provided as a plurality of tracking devices along an axial length of the energy providing component 214, such as along an axis 372. Further, the tracking device 370, even if provided as a single tracking device, can be provided at any appropriate location such as at or near the distal tip 220. The distal tip 220 may include a diffusing element that diffuses energy transmitted by the energy delivery component 214. Accordingly, the tracking device 370 may be positioned at or just proximate of an end 220 a of a diffusing element or the distal end element of the energy delivery component 214.

In addition or alternatively to the coil elements 376, microcoils 377 a and 377 b may be included as the second or separate tracking device 370 on the energy transmission component 214. The microcoils 377 a, 377 b may be positioned on an exterior surface of the energy transmission component 214 or may be incorporated into a cladding layer 219 a that may surround a fiber optic portion of the energy transmission component 214. The microcoils 377 a, 377 b may be positioned at any appropriate location on the energy transmission component 214 similar to the conductive coils 376. Accordingly, the microcoils 377 a, 377 b may operate as the tracking device 370 either alone or in combination with the conductive coils 376.

By providing the tracking device 52 on the housing 210 the housing 210 can be navigated into the patient 14 such as to the tumor 250. A position of the housing 210 can be illustrated on the display device 66 such as relative to the image 64 of the patient 14, such as including an image of the brain. Further, the tracking device 370 can allow for determining and navigating the energy delivery component 214 relative to the patient 14, as well. Therefore the housing 210 may be positioned within the patient prior to positioning the energy delivery component 214 in the patient 14, however, the position of the energy delivery component 214 can be separately known or determined based upon tracking the tracking device 370 and the navigation processing unit determining the position. In this way the housing 210 can be positioned into the patient 14 at a first selected time and the image delivery component 214 can be positioned in the patient 14 at a second time, different, such as after, the positioning of the housing 210, while still allowing a determination of a position over the image delivery component.

Positioning of the distal end 220 of the energy delivery component 214 can assist in providing an efficient and discrete therapy to the patient 14. For example, as noted above, delivering thermal energy to the patient 14 may be provided by transmitting energy, such as laser energy, with the energy delivery component 214. The laser energy may be delivered diffusely through the distal tip 220, such as with a diffusion element (e.g., a diffusion element as disclosed in U.S. Patent Application Publication No. 2012/0245573, incorporated herein by reference). Therefore the position of the distal end 220 may be selected to be substantially, discretely, and precisely positioned within the patient 14.

Further, during a time of therapy it may be selected to move the distal end 220 of the energy delivery component 214 without moving the housing 210. For example, the distal end 220 of the energy delivery component 214 may be moved along the length or along an axis 211 of the housing 210 to different axial positions within the housing 210. Moving the energy delivery component 214 may provide the energy, such as thermal energy, to different locations along the housing 210. Therefore, tracking energy delivery component 214 separate from a position of the housing 210 can assist in determining, substantially, precisely, (such as within about 0.1 mm to about 1 mm) the position of the distal end 220 for continuing or altering therapy to the patient 14.

With reference to FIG. 7, the laser system 202 can be operated to perform a selected procedure, as illustrated in flowchart 400. Generally, the procedure can start in a start block 402. The procedure may then include acquiring initial image data of the subject in block 404. The initial image data may include MRI image data, such as acquired with the imaging system 12, and displayed on the display 66. The initial image data may be used to plan a procedure, such as determining a location of the region of interest 250 and selecting a trajectory and selected positions for positioning the instruments 200 and/or the distal end 220 of the energy delivered component 214.

After determining or selecting a plan, user 54 or other appropriate instrumentation such as a robotics system, may move the instrument to the region of interest in block 410. While the instrument is moved, the instrument may be navigated in block 412. As discussed above, navigation of the instrument may include navigation of an entire portion of the instrument 200, or selected portions thereof. For example, the housing 210 may be navigated separately from the energy delivery component 214. Nevertheless, the instrument can be moved to the region of interest in block 410 via the navigation block 412.

Once the instrument is at the region of interest, initiation (or continuation) of energy delivery occurs in block 420. As discussed above, the delivery of energy may increase the temperature in the region of interest 250. Therefore, determination of the temperature and or temperature profile of the region of interest in block 426 may occur. The determination of the temperature in the region of interest 426 can be based upon the sensed temperature, such as with the temperature sensor components 290 a, 290 b. Further, as discussed above, the temperature may be sensed at the varied positions within the region of interest 250, including along a length of the instruments 200 and at a distance away from the surface 230 of the housing 210.

After determining the temperature in the region of interest in block 426, a determination of whether a selected temperature is achieved occurs in block 430. The determination may be made by evaluating the determined temperature and/or temperature profile form block 426. For example, a user may view the icon 292′ and determine if the illustrated temperature is the selected temperature. Alternatively, or in addition thereto, one or more of the processing units may compare the determined temperature from block 426 to a planned temperature that may be determined prior to the procedure and stored in the memory 62. The processing unit may then recall the planned temperature and/or temperature profile and compare it to the determined temperature in 426 and automatically determine if the selected temperature have been achieved.

If a selected temperature is not achieved in block 430, a “no” block 432 may be followed to continue energy delivery in block 420. Therefore, energy delivery can be initiated and continued in block 420 until the determined temperature in block 426 is determined to be the selected in block 430. The temperature determination in block 426 may be substantially real time, such as determined every 0.1 seconds to about 30 seconds, or other appropriate frequency. Thus, the determination of whether the selected temperature is achieved in block 430 may be performed at the same frequency.

Once the selected temperature is determined to be achieved in block 430, a “yes” block 440 may be followed to determine whether to move the device to a new position in block 446. If it is determined to not move the instrument 200 to a new position, a “no” path 450 may be followed and the procedure may end in end block 452. Ending the procedure in block 452 can include confirming that a selected tissue has been killed in the region of interest 250, closing a burr hole in the patient 14, and other appropriate procedures based upon a selected procedure being performed with the device 200.

If it is determined in block 446 to move the device 200 to a new position, a “yes” block 460 may be followed to block 410 to move an instrument to a region of interest which may be determined than a first region of interest or may be within the region of interest at a second position. The initiation of delivery of energy in block 420 can then be reinitiated at the new position and the method 400 may then be followed as discussed above.

As discussed above, movement of the device 200 to a new position in block 446 can include moving the entire device 200 or only moving the energy delivery component 214 to a different position within the housing 210. Again, due to the tracking devices 52, 370, the housing 210 can be navigated separately from the energy delivery component 214. Furthermore, icons can be superimposed on the image 64, including an icon 460 (illustrated in FIG. 1) to illustrate a position of the instrument 200, or portions thereof including the housing 210 or the energy delivery component 214, for viewing by the user 54. As discussed above, the patient space and image space may be registered to allow for the illustration of the icon 460 at the correct position. The user 54 can therefore navigate and view the location of the device 200 relative to the image 64 to determine whether a plan is being followed, a location of the device 200 is being achieved, and other position information regarding the device 200 relative to the patient 14.

It is understood that the method illustrated in the flowchart may include portions executed by one or more of the processing units discussed above. For example, determination of a temperature in a region of interest in block 426 may be performed by receiving a signal from the temperature sensors 290 a, 290 b and calculating the temperature based on the signal. Further, thermal energy may be ceased or the method may be ended automatically if the determination in block 430 is to follow the “yes” block 440. Thus, automatic shut-off of the laser system 202 may occur to assist in more closely following a plan or assisting in assuring that only a selected temperature is reached.

The temperature sensors 290 a, 290 b also allow for a real time determination of a temperature in the region of interest. As the temperature sensors are at the region of interest 250, the signals received are based on the current (e.g., within a reaction and transmission time of the selected temperature sensor component device, including within 1 second or less) temperature in the region of interest 250. Thus, the thermal therapy may be delivered accurately and with tight controls. Further, the temperature sensors 290 a, 290 b eliminate the need for an external device to measure or determine the temperature of the selected region, such as using MRI data.

Accordingly, the navigation system 10 and the temperature sensors 290 a, 290 b allow the device 200 to be positioned relative to the patient 14 without requiring continuous or intermittent imaging of the patient 14 during the procedure. The temperature sensors 290 a, 290 b are used to sense the temperature within the region of interest 250 to determine whether a selected temperature has been achieved. Achieving a selected temperature may allow a therapeutic result on the patient 14. Further, the navigation system 10 can be used to navigate the instrument 200 to a selected position within the patient 14 without using the imaging device 12 to image the patient 14 during or after movement of the device 200. Therefore, the imaging device 12 can be used to acquire image data of the patient 14 prior to positioning the instrument 200 within the patient 14 and performing a thermal energy treatment on the patient 14. The imaging device 12 may not be necessary during any other portion of the procedure to provide thermal energy to the patient 14 with the device 200. Thus, the imaging system 12 may only be required to acquire initial image data for planning and navigation and not for performing movement or thermal therapy on the patient 14.

Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 

What is claimed is:
 1. A system to measure temperature in a region of interest, comprising: an instrument assembly including: an exterior housing have an external wall defining an internal blind bore extending a first length from a first housing end to a second housing end and configured to be moved to a position within a volume, an energy delivery component extending a second length from a first energy delivery component end to a second energy delivery component end and configured to be moved to a position within a volume and deliver energy to affect a thermal therapy at a region of interest within the volume outside of the exterior housing, wherein the energy delivery component is moveable within the exterior housing; a first temperature sensor fixed near the first energy delivery component end to sense a temperature within the region of interest a distance spaced away from the external surface of the housing; an energy source configured to deliver energy through the energy delivery component to affect the thermal therapy in the region of interest; a tracking device fixed near the first energy delivery component end; a processor configured to execute instructions to: determine a temperature profile within the region of interest based on a signal from the first temperature sensor, and determine a position of the instrument within the region of interest; wherein the thermal therapy is operable to increase a temperature in the region of interest.
 2. The system of claim 1, further comprising: a display to display an image representing the region of interest and an icon representing the determined position of at least a portion of the instrument assembly.
 3. The system of claim 1, wherein the display device is further configured to display a temperature icon to represent the determined temperature profile including a representation of a physical temperature image of the measured temperature profile.
 4. The system of claim 1, further comprising: a second temperature sensor spaced apart from the first temperature sensor, wherein the second temperature sensor is configured to sense a temperature at the surface of the exterior housing.
 5. The system of claim 4, wherein the first temperature sensor includes an ultrasound temperature sensor.
 6. The system of claim 1, wherein the processor is further configured to execute instructions to stop delivery of energy when the temperature profile reaches a selected temperature.
 7. A system to measure temperature in a region of interest, comprising: an instrument extending a length from a first end to a second end and configured to be moved to a position within a volume and deliver a laser light to provide a thermal therapy to a region of interest within the volume; a temperature sensor connected to the first end to sense a temperature within the region of interest; an energy source configured to deliver energy through the instrument to affect the thermal therapy in the region of interest; wherein the thermal therapy is operable to increase a temperature in the region of interest.
 8. The system of claim 7, wherein the temperature sensor is connected to the instrument at a position a distance from a distal terminal end at the first end.
 9. The system of claim 7, wherein the temperature sensor includes a plurality of temperature sensors.
 10. The system of claim 9, wherein the plurality of temperature sensors are spaced along at least a portion of the length of the instrument.
 11. The system of claim 10, wherein each temperature sensor of at least a sub-plurality of the plurality of temperature sensors is configured to measure the temperature of the region of interest at the surface of the instrument.
 12. The system of claim 10, wherein each temperature sensor of at least a sub-plurality of the plurality of temperature sensors is configured to measure the temperature of the region of interest at a distance away from the surface of the instrument.
 13. The system of claim 12, further comprising: a processor configured to execute instructions to determine a temperature profile around the instrument within the region of interest based at least on the sensed temperature from the plurality of temperature sensors.
 14. The system of claim 7, further comprising: a tracking device having a coil connected near the first end of the instrument; a navigation processor configured to determine a position the tracking device; and a display device configured to display an image representing the region of interest superimposed with an icon representing the determined position of the instrument.
 15. A method to measure temperature in a region of interest, comprising: directing laser light energy through an emitting portion of an energy delivery component to heat the region of interest; determining a temperature in the region of interest with a signal from a temperature sensor connected relative to the energy delivery component near the emitting portion; determining when a selected temperature in the region of interest is achieved by evaluating the signal from the temperature sensor; and ceasing the heating of the region of the region of interest when the selected temperature is determined to be achieved.
 16. The method of claim 15, further comprising: tracking the energy delivery component during movement of the energy delivery component into the region of interest.
 17. The method of claim 16, further comprising: displaying an icon representing a position of the energy delivery component based on the tracking of the energy delivery component.
 18. The method of claim 15, further comprising: operating the temperature sensor to sense a temperature a distance from the energy delivery component.
 19. The method of claim 18, further comprising: operating a processor to determine a temperature profile relative to the energy delivery component.
 20. The method of claim 19, further comprising: viewing a display of a temperature icon representing the determined temperature profile. 